The purpose of this investigation is to solubilize, purify, isolate and characterize tumor rejection antigens from 5-bromodeoxyridine-grown mouse melanoma cells and to isolate and characterize plasma membranes from the treated and untreated cells. The treated cells are non-tumorigenic and highly immunogenic when inoculated into adult C57BL/6J mice, protecting them against tumor formulation when subsequently challenged with untreated tumorigenic non-immunogenic parental melanoma line. Purified plasma membranes will be prepared by gradient centrifugation and will be monitored for purity and yield by appropriate biochemical assays. They will be monitored for tumor rejection in vivo, as will soluble fractions prepared from the membranes. These will be purified further by chromatography, including lectin affinity columns. Similar protocols will be used with a mouse mammary adenocarcinoma after successful procedures are worked out with the melanoma system. Biochemical studies will continue to be carried out on glycoproteins and glycosaminoglycans in the melanoma system. The ultimate aim of these studies is to use them as model systems forming a basis for safe immunization of melanoma and breast cancer patients after removal of their primary tumors. The biological assay used in the model systems should provide strong validation that the fractions obtained are those inducing tumor immunity.